Such casing normally include leg elastication which, when the article is worn, embrace the wearer's thighs so as to prevent the occurrence of gaps between the article and the wearer's thighs and therewith provide a seal against lateral leakage. The leg elastication will often consist of elastic threads or elastic bands which are enclosed between the two layers or sheets from which such casings are normally made. It is also known to use elastic devices in so-called all-in-one diapers which function to gather together those side-parts of the casing material which lie outside the absorbent pad in a manner to lift these parts in at least the crotch-part of the article, so as to form barriers against lateral leakage. Although this design will normally function in the manner intended, there is a danger of the upstanding side part of the casing being folded inwards over the absorbent pad when the diaper is placed in position on the wearer. Further, when narrow elastic threads are used, there is a danger of the threads chaffing against the wearer's skin.